http://dmitrysotnikov.wordpress.com...computers/
NotLoggedOnFor – to specify the number of days since last time the account was used to log on (note that LastLogonTimestamp parameter is used, which means that it is replicated between DCs and the retrieval is fast and works with any domain controller, but it requires 2003 or later AD schema and is only replicated every 9-14 days (so please don’t specify values less than 14)